US1020699A - Centrifugal pump. - Google Patents

Description

Patented Mar. 19, 1912.

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W. KIBSBR. OENTRIFUGAL PUMP.

APPLICATION FILED JAN.12,1909.

Patented Mar. 19, 1912.

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Walter'KieZer', 5 g o lt,

Inventor" W. KIESER. GENTRIPUGAL PUMP.

APPLICATION FILED JAN.12.1909.

Patented Mar. 19, 1912.

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" UNITED STATES PATENT oFF o sures amass; ornmtmn, GERMANY, Assmivor; T0. GEivEnAL anaemic oomrhiir,

A COIQPOBATION OF NEW-YORK.

oEN'rRIFUGAL PUMP.

Specification of Letters Patent. PfltenY-lefl Dial 4519,1912, Applicationiilled January 12, 19 9. Serial n. 6 1,978.

Tniow that -I, KInsER, C1t1Z0n .0f,SW1tZerland, residing at Berlir Germanyfhave invented certain new andv useful litnprovements in Centrifugal Pumps, of which the following is a specification.

This invention relates to centrifugal Qpumps'inwhich the fluid to be pumped is driven by. one or more rotating impellers,

each of which receives fluid in a chamber concentric with thesh'aft by .-.which it is rotated, and'thr'ows it out through orifices or nozzl s in its periphery. .In such pumps, it

is common to produce an equalization of pressure between" the two sides of theirspel ler wheel by means of a poi-tin the interior-wall of the wheel.

This does not, however, perfectly equalize the pressure, because there still remains an axialthrust on the wheel.

The objectof my invention is to provide anautomatic equalization of the axial thrust. I ,r

In the accompanying drawings, Figure 1 is a side elevation of a turbine-driven centrifugal pump embodying my improvements; Fig. 2 is. a vertical axial section of the pump proper;-Fig. 3 is an enlarged section of one ofthe impellers; Fig. 4 is a similar section of a modified impeller; and

' Fig. 5 is an enlarged fragmentary section of another modification.

The pump -1 and its driving turbine 2 are mounted on a. common pedestal 3 so as to constitute a self-contained unit. The shaft 4 may be common to both machines or it maybe made in two parts and unitedby a-qcoupling as shown. It .is suitably jourflnaled in bearings 5, 6, the former inounted on'one end of the; pedestal .and the latter supported on the-head of the pump. In the same journal-box 7 which contains the Y bearing 6 is a thrust bearing 8. The tur- .bine overhangsthe pedestal beyond the. '45

bcarin '5 being preferably supported by. a bracin 9 extending from the journal box 101 The pum islocated at the other. end of the pedestal, t e lower half 11 of the pump casing'lbeing' preferably castintegral with s'ald-pdestal. The upper half 12 ofsaid casin .meetsthe'lower half on a horizontal airia.l g p lairs,3 One head 13 is integral with 1th .'asingfwhile the other head 14 is re-" .meyible and has a flange 15 by whlch 1t can be bolted to the casing. In each head is a and diaphra thereto 13 "means of which"sealing fiui may be a mittcd' Stufiin boxes 18 are pro-4 vided for the shaftgat one end of the pump.

The number of impellers .19 may be varied g1 dlti'ercnt umps, Ellie oneiillustratid"; ree are s ow f-Ino' rigi yon t e. shaft inside The number; of.

vanes or bIadeSYonKeach propeller may. also j be varied. By means of end rings 20 and .diaphragms 21;eac h';.i1npe'ller is in'closed in' its own chamber from which the nozzle or diffusing passage or passage's22 extend radially outward 'throughthe diu p'hragms. In the halves of the-casing ar'e'circumferc'ntial grooves 23 for receiving the liquid flowing through said passages 22 and guiding it around the edgesof the diaphragms into radial channels- 24 in said diaphragms,

through which the liquid' is conveyed tothe inlets 25 of the. successive impellers.

Byarrangingthe parts in the manner de- A scribed the machiningthreof is a very simpleoperatiom: Ordinarily the halves of the casing will'be bolted together and each coniplcte circumferential groove finished by the same machine operation or operations.-

Sincethe surfaces forming the groove or passage can bemachined and thus made smooth the efiiciencv of the pump may be made high because of the fact that resistance to flow of the liquid being pumped will be a minimum. The liquid is'fed to the inlet of the first impeller-by a supply pipe 26 and issues from the last impeller and its surrounding nozzle into a delivery pipe 27.

The construction of the impeller is best shown in' Fig. 3. The discharge portlon 28 has 'parallel'outer walls 29; 30 lying in planes perpendicular to the axis. The hub lar and circumferential surfaces 31, 32. The

as as a series of steps fiormed by perpendicu-' walls ofthechmnber in which the impeller rotates are formedpreferably by rings 33 let into-.suitable recesses in the end rings shape with t e impeller, leaving a narrow clearance space between the several adjacent surfaces.

The path of the liquid is from'the supply pipe 26 through the three impellers in series s, and they correspond in to the delivery pipe 27. The back pressure on the impellers sets up a thrust lengthwise of the shaft and toward the left in all the figuresof the drawings This thrust can be partly relieved by the port-s34 which admit the pressure to the space between the im-.

peller and the next diaphragm or the head 14. The sheet of liquid thrown out through the annular dischargeportion of the impeller is received by the stationary difluser, but

the back pressure causes some of the liquid to flow laterally over the edge of the imp'el- 1' ler into the clearance spaces between said impeller and the djoining rings. If now the impellerv shifts; bodily toward one of said rings it is evident that the clearances between all cylindrical surfaces Wlll. remain unchanged, while those on one Zigzag the impeller and between the surfa erpendicular tothe axis will decrease and. those -..9!. ..,th.e.-0ppositeSide-ifiErease. Under nor-- mal conditions there are multiple leak paths for the fluid leaving the impeller, one right and one left, and the amount of fluid flow- ,ing through them depends upon the restriction or restrictions therein. Take the case of 'the structure inFig. 3 for example and assume the impeller shifted to the left. The 25.

outlet for the.leakage fluid on the left-hand side is decreased while the inlet remains the same, hence the pressure in the side chamber 'will build up and tend tothrust the impeller back to its normal and stable position. This.

action is assisted by the stepped'construction v of theimpeller which affords .a tortuous passage for the liquid tending to'prevent I it from escaping too freely, and .iorms a series of chambers in which the pressurecan be built up. The condition of affairs on the right of the impeller is reversedfthat is to say the inlet remains the same but the outlet area is increaseddue to the separation of the perpendicular surfacesand by such an amount as will cause the'pressure of the leakage fluid in the side chamber to drop and thus in a negative way assist in reestablishing the proper balance of the 1mpeller. It is to be observed also that the port 34'performs' its function of equalizing pressures on opposite sides of the impeller in so far as possible.

In the modification shown in Fig. 4, the edge of the impeller is grooved circumferentially and receives the converging throat portion 35 on the diffuser, said throat beingpreferably made in a ring 36 clamped against the wall of the impeller chamber by the rings 33. This construction pro .vldes the impellers with lips 37 which are adapted to close toward or against one side or the other of the throat 35 as the impeller shifts toand fro. The rings 81 or their equivalent stationary elements are provided with grooves 38 which form chambers adjacent to'the radial surfaces 31 of the hub adapted to' retain a certain body of liquid at all times and thus equalize the flow of liquid from one hamber to the next] Assuming that the impeller shifts to the left from any cause, the passage for fluid on the right of the nozzle is restricted by the lip and hence less fluid can flow, and since the outlet area between the circumferential surfaces at the stepped'port-ion of the impeller is virtually the, same, or at least is no smaller, the fluid pressure in the right hand side chamber will be less than before. On

the left-hand side the conditionsiaie reversed.v The area of the outlet remains 'the 7 same or virtually so while the inlet passage to ,the'cliamber on that-side is considerably large'r hence the pressure in the lefthand side 0 amber or chambers will morenearly approach that of the fluid leaving the impeller, and since this pressure is superior to that on the opposite side of the impeller the latter will be shifted to the'right and to its normal position where it is in a state of equilibrium. In connection with balancing the thrust on these impellers it'is to be noted that the position of the shaft in its bearings will be determined by the joint action of all of the impellers, each impeller performing its share of the work, whatever that may be.

For certain pumps, I find it desirable. to make the clearances between the cylindrical surfaces greater on one side than on'the other. As an example-I may use a clearance between annular surfaces on the right hand side of the impeller of .3 of a millimeter and on the left .25 of a millimeter. This arrangement is illustrated in a somewhat exaggerated manner in Fig. 4, and also in Fig.

5. as applied to the pump of the type shown in Fig. 3. By varying the clearances on one side or the other a certain definite thrust or bias may be created at all times which op: poses the normal thrust due to the act-ionof the fluid in the impellers.

If desired, the space or chamber at one or both sides of the nozzle may-bewidened,

and a flange 39 located at the inner end to' narrow the passage for the liquid into the" grooves 38.

In accordance with the provisions of the patent statutes, I have described the principle of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof; but I desire to have it understood that the apparatus shown is only illustrative, and that the that the spaces between perpendicular surfaces will vary in width with the axial shift ing of the impeller, and the balancing pressure in said spaces will vary inversely with their width.

2. A centrifugal pump having an impeller provided with smooth lips on each side of its discharge portion, and having also steps on each side of said portion, a diffuser having a receiving portion entering between .said lips, and stationary elements having grooved steps corresponding with the steps on the impeller.

3. A centrifugal pump comprising a casing having inlet and discharge ports, an impeller located therein which receives the fluid to be pumped from one side, a port in the body of the impeller to approximately balance the pressures exerted thereon, an-

auxiliary balancing means comprising parts located on each side of the impeller and havingopposed perpendicular and circumferential surfaces of revolution arranged in a stepped series, the said surfaces being separated by clearance spaces to which the flllld at the discharge pressure of the impeller has- 'with axial shifting of the impeller,'the said cylindrical clearance spaces on one side of the impeller-being greater than on the other; In witness whereof, I have hereunto set my hand this 23rd day of December,l908. \VALTER KIESER. Witnesses FRIEDRICH GANZERT, LUDWIG CUBELIC.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents Washington, D. G.

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